I got these last year: Amazon.com: Rugged Ridge 11025.02 Black Mirror Relocation Bracket - Pair: Automotive
Cost me $22, now at $26 (plus $10 S&H - boo)
I moved the mirrors last spring when the hard top came off, then last fall I relocated the mirrors back to the doors for the winter. This spring I moved the mirrors again, and so on. Passenger-side view is slightly obstructed with the hard doors on (maybe 40%), but I can see almost all of the mirror with the doors off. Drivers-side is completely unobstructed.
I drove with no doors one summer years ago (96, maybe?), but technically you can
get pulled over and ticketed for not having mirrors - it's a 'primary offence'. I figure $30-$40 bucks is worth it to avoid giving them a reason to pull me over, and I suppose it does make a little bit safer to drive.
Also, I think the Jeep looks funny without mirrors - like a head with no ears.